The grades on a geometry midterm at Loyola are normally distributed with $\mu = 70$ and $\sigma = 2.5$. Michael earned a $69$ on the exam. Find the z-score for Michael's exam grade. Round to two decimal places.
Explanation: A z-score is defined as the number of standard deviations a specific point is away from the mean We can calculate the z-score for Michael's exam grade by subtracting the mean $(\mu)$ from his grade and then dividing by the standard deviation $(\sigma)$ $ { z = \dfrac{x - {\mu}}{{\sigma}}} $ $ { z = \dfrac{69 - {70}}{{2.5}}} $ ${ z \approx -0.40}$ The z-score is $-0.40$. In other words, Michael's score was $0.40$ standard deviations below the mean.